This link is a treasure trove of all these great quotes of famous and infamous celebrities set up as a convenient soundboard. The sound bites are arranged in such a way that you can compose your own phrases and sentences into a full conversation. It is so comprehensive you could even call your buddies and have Britney Spears talk to them, or have Dr. Phil tell your boss, "do you understand at all what I am saying", or Jack Nicholson call someone up that owes you money and persuade him in his own special way to pay up by stating "Are you trying to intimidate me with that party attitude?".
Check it out here, you will have hours of fun.